Sprue-forming device



March 1o, 1942. P. .PERAZ 2,275,806

v -sPRUE-FORMING DEvIE Filed Dec. 414, 41940 1N VENTO/e BY PETER l.. PERAZO #my n ym? Patented Mar. 10, 1942 UNITED STATES Parametri-cs Application December 14, 1940, Serial No.` 370,196 7 claims. (C1. afi-'38) in a mold.

Another object is to provide a sprue-forming device in which the basin pattern provides a guideway which sealedly and slidably receives the sprue punch without confining the punch Vto a l5 fixed angular disposal with respect to the basin pattern.

The invention possessesother objects and features of advantage, some of which, with the foregoing, will be set forth -or be apparent, in the fol- 20 lowing description of typical embodiments thereof, and in the accompanying drawing, in which,

Figure 1 is a side elevation of a squeezer board carrying a pair of sprue punches embodying the present invention, said punches being shown asf-25 partly engaged in the molding sand in the upper, or cope, section of a molding flask which contains a pattern and is shown in section at the plane of the punches.

Figure 2 is an enlarged axial section of a sprue"` 30 punch and basin assembly of Figure 1, the view being taken at 2 2 in Figure l;

Figure 3 is a fragmentary perspective View of a sealing ring of the structure of Figure 42.

Figure 4 is an axial section corresponding tor that of Figure 2 and showing a diierent embodiment of the invention.

Figure 5 is a fragmentary perspective View of a sealing ring of the structure of Figure 4.

By way of illustration, Figures 1 to 3 show thefgfffo features of present invention as incorporated in casting apparatus which includes sprue punch assemblies mounted on a squeezer board 5 which is provided for eompacting the molding sand 6 in a mold ask section I and about a pattern 8;- which engages against a match-plate 9 on which the iiask section rests during the formation of the molding space and sprue passages in the section. The flask section 'I is provided at its opposite ends with members II which receive pins I2 for.r simultaneous registration in openings through the match-plate 9, or in members II mounted on the lower flask section (not shown) for assuring an aligned registration of the iiask section 'I with the match-plate or with the lower flask sectionsifl Thepattern 8 may be that ofv an article to be cast in the section 1, with or without runner extensions, or may provide a distributing gate for castings to be produced in the section or inV an underlying flask section.

Openings I3 are provided through the squeeze board 5, and basin pattern members I4 and I5 are mounted on the underface of the board with openings I6 therethrough in alignment with the different openings I3. The members I4 and I5 may be of metal, are hollow from their board-engaging faces, and generally taper from said faces. Punches I1 extend freely through the different openings I6 for forming sprues in the sand of the mold as the sand is compacted beneath the squeeze board 5.

In the present assembly, the member I4 is of generally frusto-conical outline with the opening I6 thereof provided at its lower face, while the member I5 is more or less oval in plan with the opening I6 thereof provided through the vlarger portions of its lower face to which its sides taper. It will be understood that the member I5 shapes a pouring basin for the passage provided by its punch, while the member I4 shapes a funnel-like upper end for the passage provided by its punch, the latter passage being utilizable as a passage for molten metal' to a mold cavity of the flask or as an air vent for such a cavity; for descriptive convenience, both of `said passages may be referred to as sprues or sprue passages.'

It will now be noted that each punch Ilcomprises a tubular element having the portion thereof which extends below a basin pattern I4 or I5 externallytapered whereby the'punch may wedgedlir engage the sand for insuring a particularly compacted condition ofthe sand adjacent the sprue bore as the punch is forced intothe sand for registration with the pattern 8, and providing for a simultaneous release of the `punch from the engaged portions of the sprue bore as its axial withdrawal is started. f The interior bore I8 of the punch is uniform beyond an inturned and sharpened edge I9 at' its free advance end'whereon the upper side of the squeeze board 5. 'Ihe bracket 23 has an intermediate portion 24 parallel to the board and having a central perforation 25 in alignment with the punch axis, and the upper end of the spring 2| is fixed to the portion 24, as by welding, with the spring coaxial with the perforation 25 thereof.

The punch I1 and its associated spring 2| are engaged for their relative adjustment longitudinally thereof. Accordingly, and as shown, the exterior of the upper punch portion may be formed with a spiral thread groove 26 having the pitch of the lower coils of the spring 2| and arranged to threadedly receive said coils whereby the punch is adjustably mounted within the lower spring portion. As illustrated, the lower spring portion which receives the upper punch portion is of. re- I duced diameter whereby the same number of spring coils may be constantly free of the punch; in this manner, the operative length of the spring is not changed when the punch is adjusted with respect to the spring. i

It will now be noted that the squeezer board 5 is shaped and adapted to slidably fit within the bore defined between the walls 21 of the flask section 1 in the general manner of a piston, and mounts cleats 28 which extend above the punchcarrying brackets 23 whereby the upper press plate (not shown) of a usual press may engage across the cleats for forcing the punch assembly on the board into the sand of the section 1 while compacting the sand beneath the board. At and around the periphery of its sand-engaging face, the squeeze board 5 is preferably provided with a protruding flange or rim 29 having its exposed face more or less rounded; as shown, the flange 29 comprises half-round molding and is operative to prevent a lateral movement of the sand from beneath the board as the latter is pressed against the sand.

For providing connected sprue and mold openings in the present fiask in connection with a pattern 8 on the plate 9, the distance from the top flask plane to the points of the pattern 8 which are to be disposed in the lines of punches are measured, and the punches are adjusted in their described mounting on the squeeze board 5 to extend for slightly greater distances from the top plane of the board than said measured distances. Since patterns in the flask may vary somewhat in depth as measured from the plate 9, the disclosed device for adjustment of the spacing of the advance end of a punch with respectto the board may be utilized for disposing the punch end as desired for providing its required contact with a point of the pattern.

Having the punch, or punches, adjusted as required, and the molding sand placed in uncompacted condition in the flask section around and above the pattern to the approximate level of the upper flask plane, the squeeze board is now deposited vertically upon the sand in the flask for effecting the entry of the punches I1 into the sand while aligning the board with the flask bore. A subsequent engagement of the assembly between the upper and lower thrust plates of a press and the operation of the press may force the board 5 into the upper end of the flask section to compress the sand while forcing the punches therethrough for resilient engagement with the contacted pattern surfaces.

When the sprue and mold spaces have been formed by the punches and patterns, a lifting removal of the squeeze board and the sprueforming elements thereon may be effected, and a subsequent inversion of the board permits a gravity discharge of the sand from within the punches. After the mold pattern has been removed from the under side of the flask section, the latter may then be combined with a previously prepared lower flask section (not shown) in a well-known manner for completing the mold space for use in casting.

It will now be noted that the basin pattern opening I6 which receives the spring-mounted sprue punch I1 is appreciably larger than the punch portion which it receives, and that a sealing ring 3| is provided to prevent the passage of the molding sand externally along the punch and into the pattern cavity. The ring 3| is xedly secured in the opening I6, is composed of a resiliently yielding material such as a rubber composition, and is arranged to resiliently grip the punch in its bore for providing the desired wiping seal thereat. The present ring 3| is formed with an annular peripheral groove 32 which complementarily receives a bead-like lip 33 defining the opening I6, and is held fixed to the basin pattern I4 by reason of the engage ment of the lip 33 in its groove 32.

Recalling that the punch |1 is mounted at the free end of the spring 2|, it will be understood that the spring 2| and the sealing ring 3| jointly permit and yieldingly resist lateral and/or angular displacements of the punch out of its normal line of disposal with respect to the board 5 which mounts it. said line usually being perpendicular to the sand-engaging face of the board as in the present apparatus. The resiliently resisted punch displacements thus permitted have, in practice, been found essential for facilitating the sprue-forming progress of the punch and the associated basin pattern toward a mold-space pattern, for insuring the provision of amore uniformly compacted sprue bore, and for permitting the flat and sealed bearing engagement of the advance punch end against the opposed pattern surface engaged by it.

In providing a mold space having a sprue passage thereto in the sand of a flask section by the use of a mold pattern and a sprue punch and a basin pattern, the sprue punch may sometimes be advantageously attached to the mold pattern, as is illustrated in Figure 4. In the present instance, a squeeze board 55 mounts a basin pattern 64 at a transverse opening |53 which is aligned with the bottom opening 66 of the basin pattern, al1 in an arrangement corresponding to the mounting of the basin patterns I4 and I5 of the embodiment of Figure 2 and for use with the flask structure shown in Figure 1. As shown, a mold pattern 58 mounts a sprue punch B1 for engagement through the basin pattern opening 65 as the squeeze board 55 carrying the latter pattern is moved toward `the mold pattern 58 for providing the casting mold about the latter and a sprue passage to the mold.

The present punchv 61 is provided with a base ilange 16 which is countersunk into flush relation with the mold pattern face from which it is to extend. Screws 11 having their heads countersunk in the flange 16 secure the flange and punch to the pattern 58 to dispose the punch in perpendicular relation to the face of the pattern which is to bear against a match-plate during the provision of the mold space and the sprue passage thereto. Preferably, a ring or pad 18 of resiliently compressible material, a sponge rubber or the like, is interposed between the punch base 16 and the pattern 58 whereby a slight angular displacement of the punch from its normal relation to the pattern is permitted and resiliently resisted. The punch 6'! is uniformly tapered and has a closed and rounded free end, it beingunderstood that only the basin pattern must displace sand as the squeeze board is moved toward the pattern to provide the basin portion of the sprue passage, and that the latter feature markedly facilitates the provision of a proper molding space with a sprue passage thereto. Also, the present mounting of a sprue punch corresponds to the mounting of a punch Il on the board 5.

A sealing ring 8l at the basin pattern opening 55 slidably and sealedly receives the sprue punch 6l in its bore as the basin pattern is moved toward the mold pattern formation of the sprue passage. In the present instance, the bore of the opening S6 is provided with an annular groove 82 which complementarily receives an outer annular portion 83 of the sealing ring 8l for retaining thD ring in the opening as the punch is moved through the ring bore. 'I'he sealing ring 8| is operative as the ring 3l of the basin pattern M, and its mounting is obviously the operative equivalent of the mounting for the ring 3i whereby the diiferent mounting devices for the sealing rings 3! and 8! are mutually substitutable in the basin structures shown. It will also be understood that the present assembly provides thek same operative benefits and advantages with respect to the lateral Inovability of the sprue punch in the sealing ring as does the first.

Instead of being formed of a hard and unyielding material, the basins ill and I5 and 64 may be composed largely or entirely of a form-retaining yielding material which is impervious to sand, it being primarily desirable that they provide a proper wiping seal for the engaged punches while permitting lateral displacement of the latter during the formation of the sprue passages. Thus, the basins might be formed of a yielding and relatively hard rubber composition to directly provide the sprue-receiving bores at thinner and/or softer portions thereof which provide the equivalent of the present sealing rings. When the sealing ring material is of a rubber or like composition, moisture of the wet molding sand will so moisten the engaged punch that it will slide freely through the ring bore, this being when the ring and punch are of dissimilar materials, as in the present case.

From the foregoing description, taken in connection with the accompanying drawing, the advantages of the invention will be readily understood by those skilled in the art to which the invention appertains. While I have described the features of assemblies which I now consider to comprise preferred embodiments of my invention, I desire to have it understood that the showing is primarily illustrative, and that such changes may be made, when desired, as fall within the scope of the following clahns.

I claim:

1. In combination with the squeeze board of a sand molding flask, a sprue punch, a basin pattern mounted on the board and providing an opening for longitudinal movement of the punch therethrough, and means operative at said opening to permit lateral displacements of the punch from its normal angular relation to the squeeze board during and following its movement through the opening while constantly providing a sand seal at the punch in the opening.

2. A structure in accordance with claim l whereof the sealing means comprises a sandimpervious ring of resiliently yielding material fixed to the basin pattern and having its bore compressedly and slidably receiving the sprue punch.

3. In combination Awith the squeeze board of a sand molding flask, a sprue punch, a basin pattern mounted on the board and providing an opening for the longitudinal movement of the sprue punch therethrough transversely of the board, and a sealing ring constantly cooperative between the pattern opening and the sprue punch therein to permit and resiliently resist laterai and angular displacements of the punch from its normal relation to the squeeze board during and following its movement through the opening.

4. In combination with a sand molding ask, a squeeze board for use with the flask, a basin pattern mounted on the board and providing an opening for receiving a sprue punch therethrough transversely of the board, a sprue punch, means v mounting said punch for its axial movement through said opening during the operative application of the Squeeze board to the sand in the flask and for its angular displacement from a normal angular relation thereof to the squeeze board, and a sealing means operative at said pattern opening to permit and resiliently resist angular displacements of the punch therein from its said normal angular relation to the squeezey board while providing a wiping seal at the punch.

5. In combination with a squeeze board for a molding flask, a sprue punch extending transversely from the board, means mounting the punch on the board for its axial displacement with respect to a normal line for its axis, a basin pattern mounted on the board and providing an opening through which Athe punch extends, and a sealing ring of resiliently yielding material wipingly operative about the punch at said basin pattern opening.

6. In combination with a squeeze board for a molding ask, a sprue punch extending transversely from the board, an helical spring coaxial with the punch and fixed to and between the punch and board, a basin pattern mounted on the board and providing an opening throughk which the punch extends, and a sealing ring of resiliently yielding material wipingly operative about the punch at said basin opening.

7. In combination with a sand molding flask use with the flask, a basin pattern mounted on the board and providing an opening for complementairily receiving a sprue punch therethrough transversely of the board, a sprue punch mounted on and extending from the mold pattern for its movement through said opening during the operative application of the squeeze board to the sand in the ask whereby the basin pattern and sprue punch are cooperative to provide a .sprue passage to the mold space provided by the mold pattern, and means at the basin pattern opening for constantly sealing the sprue punch therein while permitting its lateral displacement with respect to the axis of the openmg.

PETER L. PERAZO. 

